Plastics compositions

ABSTRACT

Thermoplastics compositions contain ketones, thioketones, oximines, imines or hydrazones as prodegradants. The preferred additives are p-laurylacetophenone and p-laurylbenzophenone.

United States Patent 11 1 1111 3,846,395

Harper et al. Nov. 5, 1974 [5 PLASTICS COMPOSITIONS 3,001,970 9 1961 Ebel et al....... 260 45.7 R 3,014,799 12/1961 Oster 260/DIG. 43 [75] Inventors: Dav! Harper; Forgle 3,300,462 1 1967 Guzzetta a a] 260/DIG.43 McKellar, both of Blackley, 3,423,484 1/1969 Allison 260/457 R England 3,444,155 5/1969 Fish 260/949 cc 3,454,510 7 1969 Newland et al. 260 949 cc [73] Assgnee' 95 chegmal s' 3,493,536 2/1970 Weisfeld 260/457 R Eng an 3,642,690 2/1972 Mills 260/457 R [22] Filed: Oct. 26, 1971 [21] Appl. No.: 192,661 Primary ExaminerI-Iosea E. Taylor Attorney, Agent, or FirmCushman, Darby &

Cushman [30] Foreign Appllcatlon Prlorlty Data Nov. 2, 1970 Great Britain 51920/70 [57] ABSTRACT 52 us. Cl. 260/949 GC, 260/DIG. 43, 260/94.76C 51 Int. Cl. C08f 27/28 Thermoplasncs ketones [58] Field 61 Search 260/DIG 43 949 cc 45 7 R tones Oximines nines hydrazones as pmdegm 2 dams Th preferred additives are p- [56] References Cited laurylacetophenone and p-laurylbenzophenonc.

UNITED STATES PATENTS 6 Claims, No Drawings 2,484,529 10/1949 Roedel 260/45.7

PLASTICS COMPOSITIONS This invention relates to plastics compositions and in particular to polyolefine compositions.

The use of disposable plastics wrappings, containers and the like and their subsequent discarding, either intentionally or accidentally, has led to the problem of plastics litter. This invention relates to a plastics composition the use of which can alleviate the problem.

According to the invention a thermoplastics polymer composition contains a prodegradant 0.001 percent up to percent by weight of either a ketone or a ketone derivative, said keytone having the general formula where R is an aromatic group, preferably a phenyl group or an alkylphenyl group; R is a substituted phenyl group, e.g. an alkylphenyl group or a saturated aliphatic group, eg an alkyl group, or R and R are both aromatic groups which are joined together either directly orvia a chain of one or more carbon atoms, and

n 1 or 2;

said ketone derivative having the formula:-

where R is a phenyl group or a substituted phenyl group,

R is an aromatic or aliphatic group, and

X is a sulphur atom, an oximino group, an imino group, a hydrazone group or a substituted derivative of one of these groups.

The preferred ketones are those in which n 1, R is phenyl and R is a p-alkylphenyl or those in which n 1, R is p-alkylphenyl and R is alkyl. Examples of these are p-laurylbenzophenone and plaurylacetophenone.

Examples of the substituted ketone derivatives, i.e., values for X, are butoximino, acetyloximino, lauryloximino groups; methyl-, ethyl-, propyl-, butyl-, cyclohexy1-, octyl-, dodecyl-, octadecyl-, phenyland substituted phenylamino groups; and phenylhydrazone, methylphenylhydrazone, methylhydrazone and octylhydrazone groups.

The compositions according to the invention are preferably polyolefine compositions, e.g. compositions in which the thermoplastics polymer is a polymer of ethylene, propylene, butene-l, and 4-methyl pentene-l and copolymers of these monomers either with each other or with other a-olefines. The ethylene polymers may be either the high density or the low density type.

In addition to the polymer and the prodegradant a composition according tothe invention may also ine ude th ddi es i arqwn snti na ly n porated in thermoplastics polymer compositions, for example in the case ofpolyolefines they-may incorporate anti-blocking agents, slip agents, anti-static agents,

' stabilisers to stabilise the composition during process- EXAMPLES l 14 Various prodegradantjs, as set out in Table 1, were incorporated into polypropylene to give final concentrations of 0.06 and 0.006 moles/kg of the final composition (about 1 percent weight for most of the prodegradants). Two sets of samples were prepared; in one set the prodegradants were added to unstabilised polypropylene in the other to polypropylene containing:

0.04 percent weight of 1,1,1-tetrakis (3,5-di-t. bu-

tyl-4-hydroxy phenyl) propionyl oxymethylmethane 0.17 percent weight distearyl thiodipropionate 0.2 percent weight calcium stearate These mixtures were pressed to a film of thickness microns using a compression moulding cycle comprising: heat at 488K for 180 seconds at a pressure of 154.4 kN/m pressed for 240 seconds at 488K and a pressure of 3.089 MN/m and, maintaining the same pressure, cool to 298K over a period of about 600 seconds.

Samples 1 cm by 3 cm were cut from the pressed film and subjected to UV irradiation in a Xenotest accelerated ageing machine. The samples were inspected daily and tested for flex-crack failure. The time to failure is taken as a measure of the performance of the additive. The unstabilised polypropylene samples were also. tested by outdoor exposure to sunlight. These tests were carried out at Welwyn Garden City, Hertfordshire, England and they began on Dec. 11, 1970. The procedure was as follows.

Speciments of foil 0.1 mm thick were mounted between Perspex (RTM) sheets with a circle 2 cm in diameter uncovered and these were exposed at 45 to the horizontal facing south. The specimens were tested for embrittlement at weekly intervals by dropping a 3.8 g mass in the form of a 7.5 mm diameter rod onto the horizontal specimen. The mass was dropped from a height of 310 mm down a vertical guide tube. Repeats with the same formulations gave identical embrittlement times.

The results of these tests are given in Table 1.

TABLE 1 H Xenotest. Days to embrittle Open Air at additive conc.(mole/kg) Test Example Weeks Prodegradant Unstabilized Stabilized 0,06 l /k 0.06 0.006 v 0.06 0:006 Prodegradant 1 9-Fluorenone 3 4 4 7 2 Benzil 2 4 2 6 3 4,4'-bis(N-dimethylarnino) benzophenone 3 3 6 TABLE l- Continued h Xenotest. Days to embrittle .Open Air at additive conc.(mole/kg) 1 Test Example Weeks Prodegradant Unstabilized Stabilized 0.06 mole/kg 0.06 0.006 0.06 0.006 Prodegradant 4 4-chloroben zo ph enone 1 1 2 6 5 2-chlorobenzophenone 1 2 6 6 3-bromobenzophenone 1 2 6 7 4-bromobenzophenone 1 2 2 7 8 4-nitrobenzophenone 1 4 2 1 1 9 4-methy1benzophenone 1 2 6 Y 10 4-methoxybenzophenone 1 3 2 6 1 l 2,4-dichlorobenzophenone 1 2 1 6 12 4,4 '-dichlorobenzophenone 1 2 2 6 13 Anthrone 1 2 1 6 14 1,2-benzl O-ketoanthracene 3 6 Blanks were also carried out to compare with results given in Table l. The results on the blanks were:

Xenotest (Stabilised) 5 days Xenostest (Unstabilised) 4 days Outdoor Test 13 weeks Thus Table 1 shows that all the prodegradants reduced .the time to embrittle in the Xenotest; in most cases there was a substantial reduction. In the outdoor test sample 8 produced a small reduction, the other samples cut the time to about half.

EXAMPLES 15 17 The prodegradants whose fomulae are given in Table 2 were blended at 0.1 percent weight with low density polyethylene. Tensile specimens, 1.5 mm thick and cut parallel to the direction of extrusion, were tested by 3 months exposure to sunlight in Florida during which time they received 40,000 Langleys of radiation. The elongation to break was measured (on duplicate samples) before and after exposure. The percentage retention of elongation is given in Table 2.

TABLE 2 Example Prodegradant Retention l5 CH COC H C, H 35 16 C H COC I-LOH 47 17 C H COC l-I CL 42 The C H was para linked.

Without a prodegradant, i.e., the blank, the low density polyethylene retained 75 percent of its extension. This clearly illustrates the effectiveness of the additives.

EXAMPLES. 18 26 and 27 29 Table 3 gives the results of accelerated ageing tests.

on polypropylene plaques stabilised with:

0.1 percent weight of 2,6-di-t.butyl-4-methyl phenol hours) for the polypropylene samples and in Table 4 (in days) for the low density polyethylene.

TABLE 3 Sample Blank Example Prodegradant (hours) (hours) 18 CaHsCO CoH4C1zHzs 16 41 19- COHISCO COCiHs 24 73 20.. CHaCOCuHiCrHs 16. 5 41 21.. CHaCOCuH4C1zH15 16. 5 41 22- CQHsCO CH4S 020611 24 73 I 23 CoH5COCoH4COCuH5 24 28 C O C12H25 (lHZOHIC O 0 01115):

Now: All COH4-2T011p5 are linked para.

TABLE 4 Example Prodegradant Sample Blank (days) (days) 27 C H,.CO.C H .C H 21 39 28 CH .CO.C 1-I,.C, H 28 39 29 C,H,,.C0.C 1-1,.CO.C H,, 21 39 Note: All CJh-groups are linked para.

EXAMPLES 30 and 31 Table 5 gives results on samples of unstabilised low density (LDPE) and high density polyethylene (l-IDPE) containing 0.1 percent of the prodegradant specified. Pressed sheet samples 1 cm by 3 cm were irradiated in Tests 1 and 2 described below. In both tests the samples were examined daily for flex-crack failure and the time to embrittlement is taken as a measure of the perform ance of the additive, shorter times indicating better performance.

In Test 1 the samples were subjected to UV irradiation using a 500 watt Hanovia 509/ 10 medium pressure UV arclight the output of which was filtered through 0.5 mm Pyrex (RTM) to remove radiation below 290 nm. The samples were rotated around the lamp at a distance of cm 14 times per minute.

In Test 2 the samples were subjected to UV irradiation using a combination of a fluorescent sunlamp and a black lamp. The samples were maintained at a distance of 10 cm from the lamps.

1. A poly-alpha-olefin composition selected from the group consisting of homopolymers and copolymers of alpha-mono-olefins having up to 6 carbon atoms which has incorporated therein as prodegradant 0.00lpercent up to 10 percent by weight of a ketone selected from the group consisting of p-lauryl acetophenone or plauryl benzophenone, [of the general formula R COR where R is a phenyl group with one of more substituents selected from the group consisting of alkyl and halogen, and where R is a alkyl group, a phenyl group or a phenyl group with one or more substituents selected from the group consisting of alkyl and halogen,] said poly-alpha-olefin composition being capable of degradation by ultraviolet light faster than a poly-alphaolefin composition without said prodegradant.

2. A composition according to claim 1, in which the prodegradant is an alkyl p-alkylphenylketone.

3. A composition according to claim 1, in which the prodegradant is a p-lauryl acetophenone.

4. A composition according to claim 1, in which the prodegradant is a phenyl p-alkylphenylketone.

5. A composition according to claim 1, in which the prodegradant is a p-lauryl benzophenone.

6. A composition according to claim 1 in which the poly-alpha-olefin is polyethylene. 

1. A POLY-ALPHA-OLEFIN COMPOSITION SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS AND COPOLYMERS OF ALPHA-MONOOLEFINS HAVING UP TO 6 CARBON ATOMS WHICH HAS INCORPORATED THEREIN AS PRODEGRADANT 0.001 PERCENT UP TO 10 PERCENT BY WEIGHT OF A KETONE SELECTED FROM THE GROUPCONSISTING OF PLAURALY ACETOPHENONE OR P-LAURLY BENZOPHENONP CONSISOF THE GENERAL FRMULA
 2. A composition according to claim 1, in which the prodegradant is an alkyl p-alkylphenylketone.
 3. A composition according to claim 1, in which the prodegradant is a p-lauryl acetophenone.
 4. A composition according to claim 1, in which the prodegradant is a phenyl p-alkylphenylketone.
 5. A composition according to claim 1, in which the prodegradant is a p-lauryl benzophenone.
 6. A composition according to claim 1 in which the poly-alpha-olefin is polyethylene. 